Hi Elton, thanks for the input. I regret that I may have been too parochial
in my presentation.
I merely used what I know about the geology of my locale, New England
[which, as you aptly pointed out, needs considerable refinement] to present
a fanciful possibility that meteorite chains impacting with enough force in
strategic areas [hot spots, etc.] punching through the crust, might initiate
separation of continental masses, creating new plate boundaries.
Thanks for the links. Unfortunately for me, they are familiar. Too much for
me to retain and integrate but I keep trying. I figure in another 20 years
or so, if I keep recognizing them I may be a step closer to understanding.
P.S. It is not impossible for rift valleys to exist at the foot of mountain
ranges.
Jerry Flaherty
----- Original Message -----
From: "Mr EMan" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Wednesday, January 16, 2008 11:47 PM
Subject: Re: [meteorite-list] Asteroid Impacts May Have Triggered
PlateTectonics(OT)
There is no evidence-- direct or inferred-- that the trace of the
eastern shoreline of North America is impact influenced. While much of
what you relate is sequentially correct it co-mingles 700+ million
years of geological history into a related event. The Connecticut
River Valley is a rift valley and not a collision boundary--Otherwise
it wouldn't be a Valley but the "Connecticut River Mountains"
Perhaps you would like to "Muse this": Avalonia
<http://en.wikipedia.org/wiki/Avalonia>
And this link for the origins of the CRV Lava flows
<http://vulcan.wr.usgs.gov/LivingWith/VolcanicPast/Places/volcanic_past_massachusetts.html>
The lava flow, now seen as prominent ridgelines overlooking the valley
lowlands, formed as basalt oozed out of faults associated with the
Eastern Border Fault ... the Connecticut Valley sequence is determined
to be early Mesozoic -- from late Triassic through early Jurassic
Periods. Between 190 and 194 my North America and Baltica rifted and
basalt erupted from where Patterson NJ lies now, through The Pallasides
on the Hudson up through the Conneticut River Valley on through the
Berkshires. This rift zone accumulated several hundred feet of basalt.
Here is what is said by the USGS CVO page:
Elton
--- Jerry <[EMAIL PROTECTED]> wrote:
...My musing only takes into account the fact that the Connecticut
River Valley, 100 miles from the coast, is thought to be the result a
collision of ancient plate boundaries. The fact the the much later
break-up occurred not there, at the Berkshire Mountains margin, but
100+ miles from the CRV, just made me wonder if another mechanism might
be at work. Granted, the coastal region, at least where glacial debris
has not cover it up, is host to a string of ancient extinct volcanoes
30 miles south of Boston through the Canadian Provinces across the
Atlantic through the Celtic isles into Scandinavia. And the "brittle"
nature of these lavas may be provide sufficient explanation for the
modern continental configuration given appropriate stresses applied
through the mechanism of tectonics. But musing doesn't cost much and
cataclysm "of the mind" doesn't hurt.
Jerry Flaherty
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